Quartier Lointain by Jirō Taniguchi

A middle-aged man, Hiroshi Nakahara, unexpectedly finds himself transported back in time to his teenage years in 1960s Japan after accidentally boarding the wrong train. With the mind of an adult but the body of a 14-year-old, he navigates the complexities of adolescence while grappling with the opportunity to alter his family's future. As he relives pivotal moments, Hiroshi gains new insights into his parents' lives and the events that shaped his own, leading to a poignant exploration of memory, regret, and the possibility of redemption.